Liquid crystal spatial light modulators (LCSLMs) are very popular at the present time and are utilized in a great variety of direct view type displays, such as digital watches, telephones, lap-top computers and the like. In general, liquid crystal devices are illuminated with a relatively large, separately mounted light source, preferably from the rear (back-lighting), so that most of the light travels directly through the liquid crystal and outwardly to the eye of a viewer. Direct view displays require a substantial amount of light for suitable viewing, generally about 25 fL to be visible in office environments and more than 100 fL to be visible in an outdoor environment. To provide this amount of light or luminance at the outlets of the LCSLMs requires a relatively bright, and large, light source.
Further, LCSLMs used in display applications require polarized light and a diffuser placed in the optical path. Light entering the LCSLMs must be polarized, and an analyzing polarizer must be placed in the path of exiting light to differentiate between which LCSLM pixels are ON and which are OFF. A diffuse element, either near the modulating LCSLM or as a screen in a projection system, must be used. Generally, the result is to produce a relatively large and cumbersome package, usually with several discrete components.
This problem severely limits the usefulness of liquid crystal displays. For example, in portable electronic devices such as telephones, two-way radios, pagers, etc. the displays are limited to a few alpha-numeric digits. Generally, if a small portable device is desired, the display must be reduced to a very small number of digits, since the size of the display dictates the minimum size of the device into which it is integrated.
One way to alleviate package size problems is to use a very small liquid crystal spatial light modulator (LCSLM) as the image source, with a magnifying optical system. This can take the form of a projection display, in which light modulated by the liquid crystal is projected by the optical system onto a diffusing screen, or it can take the form of a virtual display, where the optical system creates a large virtual image of the small real image created by the LCSLM.
By using the LCSLM in a reflective mode, a reflective LCSLM is formed, which can be built onto a silicon substrate that contains the drive circuitry and other related electronics. When using this configuration as a virtual image display, the number of discrete components still results in a large and cumbersome package. At present, it is extremely difficult to provide a sufficiently large light source, and to mount the light source and the polarizers so that the reflective LCSLM is properly illuminated and can be viewed conveniently.
Thus, it would be beneficial to have reflective LCSLMs with improved packaging and lighting so they would be more versatile.
It is a purpose of the present invention to provide new and improved integrated electro-optic packaging for reflective spatial light modulators.
It is another purpose of the present invention to provide new and improved integrated electro-optic packaging for reflective spatial light modulators utilizing improved light sources.
It is still another purpose of the present invention to provide new and improved integrated electro-optic packaging for reflective spatial light modulators which are useful in forming a virtual image.
It is a further purpose of the present invention to provide new and improved integrated electro-optic packaging for reflective spatial light modulators which is small and compact enough to be utilized in portable electronic equipment.
It is a still further purpose of the present invention to provide new and improved integrated electro-optic packaging for reflective spatial light modulators which requires a sufficiently small amount of power to be utilized in portable electronic equipment.
It is yet another purpose of the present invention to provide new and improved integrated electro-optic packaging for reflective spatial light modulators which includes molded components that are easily and inexpensively fabricated and assembled.